Generation of different phases of a signal may be desired in several solutions. One of them are for providing beamforming of a radio frequency, RF, signal received or transmitted using a plurality of antennas.
Different phases of a signal may be provided by for example delay transmission lines, which has the drawbacks of consuming a fairly large area and that a difference in insertion loss between a signal that has passed through the delay transmission line and one that has not, and they will become different in amplitude.
Another way is to use an all path LCR filter to generate the different phase versions. Insertion loss is low in such an arrangement. However, such a solution is sensitive to circuitry connected to the respective outputs and the capacitive load thereof, which may ruin phase and amplitude balances of the phase versions of the signal.
Another way is to use a polyphase filter, for example a polyphase filter 102 as illustrated in FIG. 1. A signal source 101, e.g. an antenna and low-noise amplifier, provides a signal to an input 104 of the polyphase filter 102 and a multiple output of the polyphase filter 102, having terminals 106 each providing different phase versions of the signal, provides the output to a respective load 114, here indicated by respective capacitive load 114.
It is therefore a desire to find a good solution for providing different phases of a signal.